1. Field of the Invention
This invention relates to multi-color dyeing of textiles and especially relates to such dyeing of carpets to obtain sharply defined color patterns thereon.
2. Review of the Prior Art
There are many decorative patterns, currently being applied to textiles, paper, and other materials by direct printing, discharge printing, silk screen printing, offset printing, and the like, which would be desirable to use on carpets. Marbleizing, veining, and such random visual effects known as segmenting and speckling are examples thereof. These decorative effects range from delicate cobwebs to impressionistic landscapes, but they have hitherto been unavailable to carpet manufacturers. The reason therefor is that it is difficult to obtain sharply defined multi-colored print effects or patterns by using randomly dispersed dyestuffs according to prior art methods, because uncontrolled colorant migration and blending cause variations in shading which detract from the appearance of the textile material.
However, a process for achieving attractive multicolor effects on textile materials with improved sharpness, uniformity and color yield and for applying sharply delineated color patterns on flat or textured or fiber-pile textile materials, substantially without the dyestuff migration that causes secondary and tertiary coloration, has been provided in U.S. Pat. No 4,264,322 which is assigned to the assignee of this application. The entire contents of U.S. Pat. No. 4,264,322 are hereby incorporated herein by reference.
This U.S. Patent provides a process for producing an aqueous gel composition, comprising an admixture of immiscible gel phases, that is adapted for applying sharply defined multicolor patterns on the suface of an article, such as a carpet. This process comprises: (1) preparing a major quantity of a first aqueous gel phase matrix which is thickened with a cationic gelling agent; and (2) dispersing in the first gel phase matrix a minor quantity of a second aqueous gel phase which is thickened with an anionic gelling agent and which contains a colorant component.
The first aqueous gel phase (i.e., the matrix phase) is present in the composition in a quantity between about 60-95 weight percent, and preferably in a quantity between about 65-90 weight percent, based on total composition weight. The second aqueous gel phase (i.e., the dispersed phase) is present in the composition in a quantity between about 5-40 weight percent, and preferably in a quantity between about 10-35 weight percent, based on total composition weight.
Two or more immiscible gel phases of the above-described second type can be dispersed in the matrix phase, wherein each of the dispersed gel phases contains a different colorant so as to provide an aqueous gel vehicle which contains a random distribution of colorant entities. The weight of the two or more dispersed gel phases can total up to about 40 weight percent of the composition.
The matrix gel phase can also contain a colorant component, preferably a dyestuff which is soluble in the matrix gel medium. The matrix gel phase can alternatively contain an anionic gelling agent, instead of a cationic gelling agent; concomitantly, the dispersed gel phase must then contain a cationic gelling agent, instead of an anionic gelling agent. The quantity of cationic or anionic gelling agent incorporated in any one of the aqueous matrix or dispersed gel phases varies in the range between about 0.05-3 weight percent, and preferably averages in the range between about 0.1-2 weight percent, based on the weight of the individual gel phases.
The term "gelling agent" means a natural or synthetic hydrocolloid which is water-soluble or water-hydratable or water-dispersible, the presence of which in an aqueous medium increases the viscosity of the aqueous medium up to and including a state of gelation.
Illustrative of suitable hydrocolloid cationic gelling agents are hydratable natural and synthetic polymers which contain a multiplicity of quaternary ammonium groups. Typical of quaternary ammonium groups are tetramethylammonium chloride and bromide, benzyltrimethylammonium chloride and bromide, tetraethylammonium chloride and bromide, tetrabutylammonium chloride and bromide, methylpyridinium chloride and bromide, benzylpyridinium chloride and bromide, trimethyl-p-chlorobenzylammonium chloride and bromide, triethanolmethylammonium chloride and bromide, and the like, wherein each of the said groups is derivatized in the form of a radical which is substituted in a hydrocolloid gelling agent by means of an alkylene or oxyalkylene linkage.
Other hydrocolloids can be employed which contain cationic groups such as acid salts of primary, secondary, and tertiary amines, or which contain phosphonium or sulfonium groups. The anion moiety associated with a cationic group include halide, sulfate, sulfonate, hydroxide, and the like.
The polymeric structure of suitable hydrocolloid cationic gelling agents include vinyl polymer and copolymers, ion exchange resins, polysaccharides, and the like. A particularly preferred class of hydrocolloids includes derivatized natural gums which contain the appropiate cationic groups. Illustrative of this class of hydrocolloids are polygalactomannan gums containing quaternary ammonium ether substituents as described in U.S. Pat. No. 4,031,307: ##STR1## wherein R is an alkyl group containing between one and about six carbon atoms, R' is an alkylene group containing between one and about six carbon atoms, X is chlorine or bromine, and n is an integer which correlates with the degree of substitution of the quaternary ammonium ether substituents in a polygalactomannan gum cationic gelling agent. The alkyl and alkylene group can contain other atoms such as oxygen, sulfur, and halogen.
The degree of substitution varies in the range between about 0.01-3. The term "degree of substitution" means the average substitution of ether groups per anhydro sugar unit in the polygalactomannan gums. In guar gum, the basic unit of the polymer consists of two mannose units with a glycosidic linkage and a galactose unit attached to a hydroxyl group of one of the mannose units. On the average, each of the anhydro sugar units contains three available hydroxyl sites. A degree of substitution of one means that one third of the available hydroxy sites have been substituted with ether groups.
Polygalactomannan gums are polysaccharides composed principally of galactose and mannose units and are usually found in the endosperm of leguminous seeds, such as guar, locust bean, honey locust, flame tree, and the like. Polygalactomannan gums swell readily in cold water and can be dissolved in hot water to yield solutions which characteristically have a high viscosity even at a concentration of 1-1.5 percent.
Guar flour, for example, is composed mostly of a galactomannan which is essentially a straight chain mannan with single membered galactose branches. The mannose units are linked in a 1-4-.beta.-glycosidic linkage and the galactose branching takes place by means of a 1-6 linkage on alternate mannose units. The ratio of galactose to mannose in the guar polymer is, therefore, one to two. Guar gum has a molecular weight of about 220,000.
Locust bean gum is also a polygalactomannan gum of similar molecular structure in which the ratio of galactose to mannose is one to four. Guar and locust bean gum as supplied commercially usually have a viscosity (at 1% concentration) of around 1000 to 4000 centipoises at 25.degree. C., using a Brookfield Viscometer Model LVF, spindle No. 2 at 6 rpm.
Also suitable are polygalactomannan gums which have been derivatized by substitution of hydroxyl groups by other ether groups, in addition to the quaternary ammonium-containing ether groups. Generally the preferred polygalactomannan ether derivatives are those which have a degree of substitution up to about 1.5.
The anionic gelling agent components of these aqueous gel compositions are hydrocolloids which have the same type of basic polymeric structure as disclosed above in the description of the cationic gelling agents, except that in place of a cationic group there is substituted an anionic group such as carboxylic acid, sulfonic acid, sulfate, and the like. Preferred cationic gelling agents include polysaccharides containing carboxyalkyl groups and synthetic polymers and copolymers containing acrylic acid, maleic acid, or benzenesulfonic acid groups, and the like.
The colorants for use in the aqueous gel compositions include the conventional anionic dyes, nonionic dyes, and cationic dyes, alone or in combination with other colorants such as pigments, powdered metals, and the like. A colorant component is present in an immiscible aqueous gel phase in a quantity which can vary from a trace amount up to about 5 weight percent or more. The average quantity of colorant in an aqueous gel phase will vary in the range between about 0.1-5 weight percent, based on the weight of aqueous gel phase. A dye colorant normally will be dissolved in the aqueous gel phase, while pigments, powdered metals, and the like are present in the form of a suspension.
Illustrative of a preferred class of colorants are disperse dyes such as are listed under the heading "Disperse Dyes" in Colour Index, 3rd Edition, Volumes 2-3, published by The American Association of Textile Chemists and Colorists.
A particularly preferred class of dyestuffs are those identified as acid dyes. A list of commercially available acid dyes is provided in Textile Chemists and Colorists (volume 8, No. 7A, pages 73-78, July 1976), a periodical published by The American Association of Textile Chemists and Colorists.
In general, it is advantageous to employ an anionic dye in an aqueous gel phase which is thickened with an anionic gelling agent, and to employ a cationic dye in an aqueous gel phase which is thickened with a cationic gelling agent.
The method which is used for dispersing a minor quantity of aqueous gel phase in a major quantity of matrix aqueous gel phase determines the resultant colorant pattern in the admixture of immiscible gel phases. Thus, a swirl or marble effect is achieved by dispersing an aqueous gel colorant phase in a matrix phase with low energy stirring, so that the dispersion is not segmented. A distribution of large specks is achieved by dispersing an aqueous gel colorant phase in a matrix phase with medium energy stirring, so that the dispersion is segmented into discrete large-size specks. A distribution of fine specks (e.g., a heather effect) is achieved by dispersing an aqueous gel colorant phase in a matrix phase with high energy stirring, so that the dispersion is segmented into discrete small-size specks.
These immiscible gel compositions of U.S. Pat. No. 4,264,322 are adapted for achieving multicolor pattern effects on rigid or non-rigid surfaces, such as textiles and particularly carpets, when employing conventional printing and coating application techniques and equipment. These immiscible gel systems are capable of providing multicolor styling of carpets which exhibit a unique combination of sharpness, uniformity, and color yield, when the carpets are dye treated in a continuous assembly such as a suitably modified Kuester-Tak apparatus.
Another process for achieving attractive multicolor effects on textile surfaces, such as carpets, with improved sharpness, uniformity, and color yield, is described in Ser. No. 062,877, filed Aug. 1, 1979; it is herein identified as the immobilized gel process. The entire contents of Ser. No. 062,877, which is assigned to the assignee of this invention, is hereby incorporated herein by reference.
The immobilized gel process utilizes an alkaline aqueous gel composition which is immobilized in the form of a random or non-random pattern, wherein the aqueous gel contains components comprising (a) a heat fixable dye, (b) a polysaccharide having adjacent cis hydroxyl groups, and (c) a borate compound which is in a crosslinking structural relationship with the polysaccharide component. The immobilized aqueous gel compositions optionally can contain one or more natural or synthetic hydrocolloid thickeners which may or may not be crosslinkable with the borate compound, e.g., water-soluble thickeners such as acrylic copolymer, poly(oxyalkylene), and the like.
This co-pending application specifically provides, for example, a process for treating and dyeing a textile material which comprises: (1) applying to the surface of the textile material an alkaline aqueous solution; (2) contacting the applied solution on the textile surface with a random or non-random pattern of an applied acidic aqueous dye solution containing a polysaccharide component having adjacent cis hydroxyl groups and containing a borate gelling agent component, wherein the said interfacing solutions together form an immobilized structural gel pattern on the textile surface; and (3) fixing the dye in the gel pattern to the textile material
These component materials may be applied in any combination and any order as long as the alkaline solution, the borate gelling agent, and a polysaccharide are not brought together until all of the materials can be on the textile surface, ready to form the immobilized structural gel pattern thereon.
The term "textile material" as employed herein, with reference both to U.S. Pat. No. 4,264,322 and Ser. No. 062,877, is meant to include fabrics, fibers, yarns, and the like. Illustrative of textile materials are woven or non-woven fabrics composed of natural or synthetic hydrophobic or hydrophilic fibers and mixtures thereof.
Well known types of fibers include polyamide fibers such as nylon 6, nylon 66, and nylon 610; polyester fibers such as Dacron, Fortrel, and Kodel; acrylic fibers such as Acrilan, Orlon, and Creslan; modacrylic fibers such as Verel and Dynel; polyolefinic fibers such as polyethylene and polypropylene; cellulose ester fibers such as Arnel and Acele; polyvinyl alcohol fibers; natural fibers such as cotton and wool; man-made cellulosic fibers such as rayon and regenerated cellulose; and the like.
The dyestuffs and preferred dyestuffs that are employed in the practice of the process of Ser. No. 062,877 include the same conventional anionic dyes, nonionic dyes, and cationic dyes and combinations thereof that are described in U.S. Pat. No. 4,264,322.
With respect to the polysaccharide component recited in steps (1) and/or (2) of the process of Ser. No. 062,877, this component can be any of various water-soluble and water-dispersible polysaccharides containing adjacent cis hydroxyl groups, i.e., pairs of adjacent hydroxyl groups capable of hydrogen-bonding and crosslinking with the borate gelling agent under alkaline conditions to form a structural gel in an aqueous medium.
Illustrative of suitable polysaccharides are 1,4'-D-mannose; ivory nut mannan; alginic acid; yeast mannan; mannocarolose; glucommans; D-arabinose and D-mannose polysaccharides; D-galactose; D-mannose, and N-acetyl-D-glucoseamine polysaccharides; and the like.
The polygalactomannan gums which have been derivatized by substitution of hydroxyl groups by ether groups, as defined with reference to U.S. Pat. No. 4,264,322, are also suitable, the preferred polygalactomannan ether derivatives also being those which have a degree of substitution up to about 1.0.
Illustrative of polygalactomannan ether derivatives are those which are substituted with ether groups which include alkoxy, hydroxyalkyl, carboxyalkyl, aminoalkyl, haloalkyl, and the like.
Depending on other factors which might affect solution viscosity, the quantity of polysaccharide (e.g., polygalactomannan gum) employed in the aqueous solution (i.e., blanket solution) in step (1) of the process of Ser. No. 062,877 will vary on the average in the range between about 0.1-2 weight percent, based on the total solution weight. The quantity of polysaccharide employed in the aqueous solution (e.g., Tak drop solution) in step (2) of the process of Ser. No. 062,877 will vary on the average in the range between about 0.05-1.5 weight percent, based on the total solution weight. Only one of the solutions need contain a polysaccharide component.
The borate gelling agent component as employed in the aqueous solution of either step (1) or step (2) of the process of Ser. No. 062,877 is selected from water-soluble compounds which release borate ions in solution. Illustrative of suitable borate gelling agents are compounds described in U.S. Pat. No. 3,215,634, such as boric acid, calcium metaborate, potassium metaborate, potassium tetraborate, sodium tetraborate, sodium metaborate tetrahydrate, sodium tetraborate tetrahydrate, sodium tetraborate decahydrate, and the like. Sodium tetraborate decahydrate is sold commercially as borax.
Boric acid is a preferred borate gelling agent in the practice of the process of Ser. No. 062,877 because of its ready availability and low cost, and its effectiveness at low concentrations. The borate gelling agent is employed in a quantity between about 0.5-10 weight percent, and preferably between about 1-5 weight percent, based on the weight of polysaccharide component in a given aqueous solution. The optimal quantity of borate gelling agent to be employed is determined by such factors as the particular species of borate gelling agent selected, the quantity of polysaccharide involved, and its specific susceptibility to crosslinking interaction with the borate ions in solution.
It is believed that the crosslinking interaction involves a hydrogen bonding mechanism between adjacent cis hydroxyl groups of the polysaccharide and hydrated borate ions: ##STR2##
An important aspect of the process of Ser. No. 062,877 is the control of pH in the aqueous solutions being employed in steps (1) and (2) of the dyeing procedures. Thus, it is essential that initially the pH of an aqueous solution which contains both a polysaccharide and a borate gelling agent is acidic, i.e., a pH below about 7. The pH preferably is in the range between about 2-6.5, and most preferably is in the range between about 3-6.
It is also essential that the pH of the other aqueous solution involved in the process of Ser. No. 062,877, which contains a polysaccharide but not a borate gelling agent, is alkaline, i.e., a pH above about 7. The pH preferably is in the range between about 7.5-12, and most preferably is in the range between about 8-11.
As a further important requirement, it is essential that the subsequent pH is alkaline when the two solutions are successively applied wet-to-wet on the surface of a textile material, and thereafter when the two contacting liquid media blend together to form an interface zone. Under alkaline conditions, crosslinking occurs between the borate gelling agent and the polysaccharide(s), and the interface zone converts into an immobilized structural gel. Any dyestuff contained in the gel mass effectively is prevented from migrating and penetrating down into the web of the textile material.
As indicated previously, the process of Ser. No. 062,877 is adapted for achieving random and non-random multicolor pattern effects on textile materials employing conventional dye application techniques and equipment. It has particular advantage when it is contemplated for the application of multicolor effects on pile-fiber textile material, wherein the textile material is dye treated in a continuous assembly such as a commercial Kuester-Tak apparatus when suitably modified.
The process of Ser. No. 062,877 has special advantage for achieving marble, heather, and resist effects, which effects are desirable for multicolor styling of textile materials. The wet-on-wet dye systems of Ser. No. 062,877 provide dye patterns which have a unique combination of sharpness, uniformity, and color yield.
In the case of disperse dyes and acid dyes, and the like, thermal fixation of the wet-on-wet dye systems of Ser. No. 062,877 is readily accomplished by steam ageing, followed by conventional washing and drying procedures. For example, a dye treated carpet can be steam aged for 10 minutes at 215.degree. F., washed with cold water, and then dried.
The thermal fixation of an alkaline dye-containing immobilized gel pattern on a textile surface is facilitated if the gel system contains an acid generating agent which is susceptible to heat activation, e.g., amine salt, ammonium chloride, and the like.
The Kuester apparatus, described in U.S. Pat. No. 3,541,815, comprises a dye pan having a roller immersed therein and a doctor blade to pick off the dye and deposit it as a moving film onto the tufts of the carpet as it passes beneath the trailing edge of the doctor blade.
Known modifications of the Kuester apparatus enable selected patterns to be applied to carpets. For example, U.S. Pat. Nos. 3,683,649, 3,726,640, and 3,731,503 describe means for separating the moving film into a plurality of streams which fall through an oscillating comb-like grid of wires which disperse the streams into droplets which are deposited on the continuously moving carpet passing therebeneath. The doctor blade may also be oscillated. In addition, a second dye-dispersing means, in the form of a trough having jet openings in the bottom, may be positioned above the grid and may be simultaneously oscillated on a different frequency.
A multi-color carpet dyeing process is described in U.S. Pat. No. 4,146,362. This process comprises the use of dyes having substantially different viscosities so that the second dye, having a sufficiently lower viscosity than the first dye, is not absorbed thereby when it is dispersed over the second dye. However, all such Kuester-type applications fail to provide sharply delineated colors and a multi-color pattern. Instead, the colors tend to blend to some degree when they overlap or are side by side.
There is consequently a need for an apparatus which can enable the aqueous gel systems of U.S. Pat. No. 4,264,322 and of Ser. No. 062,877 to be applied to textile surfaces, particularly to carpets, so that their unique combinations of sharpness and uniformity of pattern can be available for carpet styling. Such an apparatus must operate in accordance with the dispersion and encapsulation characteristics of the several aqueous gel phases, wherein energy must be applied in a carefully controlled manner.